Gomis was red carded and Darren Dods headed an own goal from the free-kick.

Jennison Myrie-Williams restored the lead with a neat chip, but Stephen O'Donnell replied from close range.

It meant a nervous finish for United, but they held out to extend their unbeaten league run to eight matches.

Defender Sean Dillon had been drafted into United's midfield in place of the suspended Prince Buaben, while David Goodwillie replaced Danny Cadamarteri in attack.

But the big surprise was a place on the bench for Scott Robertson, who has been out for two months with a groin problem.

St Mirren's only change saw striker Michael Higdon come in for Andy Dorman after the midfielder was ruled out for up to six weeks with a hamstring injury.

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But it was St Mirren who dominated possession early on and Hugh Murray volleyed over a waist-high Jack Ross cross after 10 minutes.

The visitors were then on the wrong end of two marginal offside decisions inside two minutes.

The first did not matter as Billy Mehmet shanked his finish, but the second saw strike partner Higdon net from Garry Brady's poke through.

The tame atmosphere on and off the field was shaken when Stephen McGinn took out Gomis in mid-air 21 minutes in and both sets of players had to be separated as the St Mirren midfielder was booked.

Higdon then missed the best chance so far when he turned Murray's cross wide from close range.

St Mirren's Garry Brady and United's Jennison Myrie-Williams had claims for penalties turned down after going to ground theatrically.

There was now an edge to the game and a goal soon followed after 29 minutes when when a perfectly weighted through-ball from Dillon allowed Casalinuovo to turn in the box, shrug off Chris Innes and side-foot past Gallacher.

Saints should have been 2-0 down seven minutes later when Dillon once again picked out Casalinuovo in the box and the Argentinian's knockdown was perfect for Goodwillie, but the striker made a hash of his finish from six yards.

Casalinuovo opened the scoring for Dundee United

However, two minutes before the break, Gallacher was left red faced when Conway curled in a free-kick after the keeper left a huge gap at his near post.

United appeared to be coasting, but the game turned in the 59th minute when Gomis was sent off for what appeared to be a slap on opposing midfielder Stevie Thomson.

And, from the resulting free-kick, Dods seemed to get the last touch to the ball under pressure from Lee Mair.

United were in danger of throwing the game away, although St Mirren were not doing themselves any favours by passing the ball more poorly than when they did not have the extra man.

However, Conway played the ball through to Myrie-Williams, who lifted the ball beautifully over Gallacher.

With United down to nine men with Dods off the field with a blood injury, O'Donnell turned the ball in with five minutes remaining.

Dundee United manager Craig Levein:

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"I now need to address the red cards we are getting, but I would not say we are, in any terms, a dirty side.

"I think four of the six red cards have not been red cards, but we can't allow it to continue.

"Morgaro is an honest boy and he tells me it's retaliation: he was elbowed in the face and he slapped him across the back of the head and the ref only sees that.

"A few things went against us, but credit to the boys, it was a fantastic match, we played some good stuff and we won the game, which is the most important thing."

St Mirren manager Gus MacPherson:

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"We can't keep coming out after games and saying we are playing well and losing the goals we are losing.

"For 30 minutes, we were controlling the game and were comfortable.

"We've been criticised in the past for being stuffy, defensive and in the last 18 months we have made a real effort to go and play football.

"You still have to have a platform at the back, but we don't have that and slackness at the back has cost us."

32:18 Corner taken by Craig Conway from the left by-line, Michael Higdon makes a clearance.

32:09 Morgaro Gomis produces a cross, clearance by Chris Innes.

31:32 Inswinging corner taken right-footed by Craig Conway, save made by Paul Gallacher.

30:44 David Barron crosses the ball, Darren Dods makes a clearance.

28:53 Assist on the goal came from Sean Dillon.

28:53 GOAL - Damian Casalinuovo:Dundee Utd 1 - 0 St Mirren Damian Casalinuovo finds the back of the net with a goal from inside the six-yard box to the bottom left corner of the goal.
Dundee Utd 1-0 St Mirren.

20:45 Free kick awarded for an unfair challenge on Garry Brady by Jennison Myrie-Williams. Jack Ross crosses the ball from the free
kick right-footed from left wing, Andy Webster manages to make a clearance.

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